Abstract
This study was carried out to isolate Salmonella from different broiler farms in Delta, Egypt and to investigate their antimicrobial susceptibility pattern with a molecular detection of genes responsible for biofilm formation and resistance to disinfectants. Five Egyptian Governorates in Delta (Dakahila, Damietta, Gharbia, Kafr El Sheik and Sharkia) during the year 2018 were included in this study. A total of 100 diseased farms were subjected for clinical followed by laboratory diagnosis. Clinical diagnosis was made on the basis of clinical history, signs and postmortem findings of the affected broiler chickens. Internal organs (liver, cecum, spleen and heart) and swabs form water pipes, waterers and feeders were collected. Salmonella was isolated with an incidence rate of (17%). The incidences of Salmonella isolation from the collected samples in Dakahila, Damietta, Gharbia, Kafr El Sheik and Sharkia Governorates were (5/29) (17.24%), (4/23) (17.39%), (3/20) (15%), (2/13) (15.38%) and (3/15) (20%) respectively. The isolated Salmonellae were identified serologically and six serotypes were reported (S. Typhimurium, S. Kentucky, S. Inganda, S. Infantis, S. Newport and S. Enteritidis). Antimicrobial sensitivity testing revealed that ampicillin – sulbactam, tetracycline and streptomycin showed higher resistance with percentages (94.1%), (94.1%) and (70.6%) respectively. Using conventional PCR technique; AdrA, gcpA and csgD genes that responsible for biofilm formation were reported in all Salmonella isolates. qacED1 gene was detected with percentages of (100%) but qacA/B and qacC/D genes were negative.

Key words: Keywords: Salmonella, biofilm, disinfectant resistance, broiler